When using Apache Camel bean integration to invoke a method on a Java bean, you can use the @XPath annotation to extract a value from the exchange and bind it to a method parameter.

For example, consider the following route fragment, which invokes the credit method on an AccountService object:

from("queue:payments")
    .beanRef("accountService","credit")
    ...

The credit method uses parameter binding annotations to extract relevant data from the message body and inject it into its parameters, as follows:

public class AccountService {
    ...
    public void credit(
            @XPath("/transaction/transfer/receiver/text()") String name,
            @XPath("/transaction/transfer/amount/text()") String amount
            )
    {
        ...
    }
    ...
}

For more information about bean integration, see Bean Integration in Implementing Enterprise Integration Patterns.

Table 18 shows the namespaces that are predefined for XPath. You can use these namespace prefixes in the XPath expression that appears in the @XPath annotation.

You can use the @NamespacePrefix annotation to define custom XML namespaces. Invoke the @NamespacePrefix annotation to initialize the namespaces argument of the @XPath annotation. The namespaces defined by @NamespacePrefix can then be used in the @XPath annotation's expression value.

For example, to associate the prefix, ex, with the custom namespace, http://fusesource.com/examples, invoke the @XPath annotation as follows:

public class AccountService {
  ...
  public void credit(
    @XPath(
      value = "/ex:transaction/ex:transfer/ex:receiver/text()",
      namespaces = @NamespacePrefix(
        prefix = "ex",
        uri = "http://fusesource.com/examples"
      )
    ) String name,
    @XPath(
      value = "/ex:transaction/ex:transfer/ex:amount/text()",
      namespaces = @NamespacePrefix(
        prefix = "ex",
        uri = "http://fusesource.com/examples"
      )
    ) String amount,
  )
  {
    ...
  }
  ...
}